Various line detectors for detecting ionizing radiation are known in the art. While such detectors provide for instantaneous one-dimensional imaging, two-dimensional imaging can only be performed by means of scanning the line detector, and optionally the radiation source, in a direction traverse to the one-dimensional detector array. Such scanning-based detection may be time consuming. Movement of the object being examined may occur during scanning, which would severely reduce the image quality obtained.
There are also known dual-energy detectors in the art, i.e. detectors, with which two images are produced using radiation of different energy and combined into a single image to enhance different elements in the image. Generally attenuation is a function of x-ray energy according to the two attenuation mechanisms photoelectric absorption and Compton scattering. These two mechanisms differ among materials of different atomic numbers. For this reason, measurements at two energies can be used to distinguish between different elements.
Dual-energy x-ray techniques can be used to identify bone tissue separately from soft tissue in medical imaging, for example, or to identify hazardous materials, for example, in baggage scanning.